Hexagonal crystals are a those type of crystal shapes and structure which are commonly found in different types of minerals and stones. Minerals belonging to the hexagonal crystal structure or crystal system, is basically from one of the seven type of crystal systems in crystallography. In hexagonal crystals and rocks, the unit cell, which is the repeating building block of the crystal lattice, has a hexagonal shape.
Key attributes of hexagonal crystals include are :
- Sixfold symmetry: Hexagonal crystals exhibit sixfold rotational symmetry around a central axis. It means that one can rotate by 60 degrees and get the same outlook.
- Close packing: Atoms or ions in hexagonal crystals are very closed to each others or can be said as closely packed together in a specific arrangement, typically forming hexagonal close-packed (HCP) or rhombohedral structures.
- Anisotropic properties: Hexagonal crystals often have different physical properties in different crystallographic directions due to their asymmetric structure.
- Common minerals: Many minerals, such as emeralds, aquamarine, all kinds of beryl, Corundum, quartz and calcite, which exhibit hexagonal crystal systems.
These crystals have unique properties from optical, mechanical, and electrical point of view. Their characteristics make them necessary and important in various scientific and industrial applications. The hexagonal crystal system is distinct and clear from other crystal systems, such as cubic, orthorhombic, monoclinic, tetragonal and triclinic, each of which has its own characteristic symmetry and unit cell shape.